A TV white space (TVWS) in a TV broadcasting (in particular, digital TV broadcasting) system means a band which is not used in a TV broadcasting band. That is, a frequency band other than a band which a primary user or an incumbent user such as a broadcast provider services by using a licensed frequency is referred to as a white space.
Since the white band, in particular, the TV white space has an excellent propagation characteristic to wider service coverage than a high frequency of 1 GHz or higher, the TV white space may be used to provide various-purpose services including public safety, a regional information providing service, Super WiFi, and the like. In this regard, developed countries including USA, UK, and the like are primarily establishing a technological standard for using the TV white space in order to efficiently use insufficient frequency resources and provide various high-quality services.
In the digital TV broadcasting system, a white band device (alternatively, TV band device (TVBD)) finds and uses an available channel. A method by which the white band device finds the available channel includes a method using a beacon, a method of sensing a spectrum, and a method using a database.
Among them, the spectrum sensing method is a scheme in which a primary user signal is sensed in a region to use the white band device and thereafter, the available channel is directly found based on the sensing result. The spectrum sensing method requires accurately sensing the primary user signal in order to determine whether the white band device can use a channel of the white space while safely protecting the primary user signal.